Mixing machine



Dec. 29, 1964 K. ENGELS 3,163,403

MIXING MACHINE Filed Jan. 13, A1961 2 Sheets-Sheet 1 Dec. 29, 1964 K. ENGELS 3,163,403

MIXING MACHINE Filed Jan. 13, 1961 2 Sheets-Sheet 2 Aer Elite States Patent C 3,l63,4lll3 BHXNG MACEHPJSE Kaspar Engels, Mannheim-Waldhof, @ei-many, assign-or to Draiswerlre G.m.h.H., Mannheim-Waldhof, Germany Filed lian. 13, 1951i, Ser. No. 82,443 Claims priority, application Germany, lian. 16, lt), D 32,359; Dec. 3, 196%, l) 352,898 Claims. {'Cl. 259-9) The invention relates to mixing machines of the type having a stationary drum and is more particularly conv cerned with a continuously operating mixing machine for mixing dilferent types of substances, out is primarily for use in cases where one of the mixing components is constituted of materials iu the form of fine dust particles. f

Mixing machines are known for this purpose which comprise a mixing drum having a material supply device at one end and a material discharge device at the other end. In mixing machines of this type the mixing shaft with the appertaining mixing tools is journalled at the drum, and the mixing shaft is provided with driving means. Y s

it is an object of the invention to provide a mixing machine constructed and operative in such a manner that independently of the materials being mixed and within satisfactory limits, and also independently of uctuations in the volume handled by the machine, completely even mixing of the substances fed into the machine isattained up to minutest lineness, and even then when it is necessary to mix into the material the most easily flying components. All oi this is to be achieved -in a mixing machine that can be operated continuously.

Accordingly the invention provides for operation of the mixing shaft at such speed of rotation that a ring of material is formed along the inner wall of the drum and that the material intake and the material discharge apertures are provided at the end walls of the drum and in such a manner that these apertures are disposed inside the circular area that is encompassed by the ring of Y material.

Known machines of the prior art involve the shortcoming that they have a tangential material intake at the feed end and tangential material output at the discharge end. This condition interferes with the forming of the material ring on the inner surface of the mixing drum which is intentionally endeavored in accordance with the Y invention.

On the other hand, it cannot be avoided in the operation of the known machines that an `air or gas lilled or at least a gas enriched space is formed in-the direction oi the mixing shaft in which a considerable air whirling effect is developed which, however, does not prevent that, for example, with additives of very readily dust forming consistency a passing through velocity of these iloating powdered components, which are carried along by the air, -is developed in this inner space which differs from the general mixing time for the other materials involved. As a result the heavy mixing load soughtV in high velocity machines in accordance with the invention is lacking. The component which is' to be admixed to the other material leaves atV the discharge end as a tree superimposed material ilow.

Since in accordance with the invention the material feed aperture and the material' discharge aperture are disposedat the end walls of the mixing drum in such a manner that these apertures are located within the circular area which is surrounded by the ring Vof material, it follows that the desired formation of the ring of material takes place to the utmostfextent without disturbink elects and that the mixing tools of the high velocity V.mixing shaft exert the great mixing effect intheV area ICC Patented Dec. 29, 1964 of this material ring, which is of decisive significance for the high quality mixed product sought to be obtained.

An essential accomplishment in accordance with the invention is the cognition that the mixing machine of the type described is not only suitable for the continuous mixing of substances of all kinds but,-in addition, provides a particularly great advantage over the prior art machines when it is used for the continuous preparation or treatment of thermoplastics and duroplastics. In that case the raw materials for the plastics are supplied to the mixing drum with the dyes, lillers, stabilizers, softeners,

lubricators and the like.

VBy using the machine in accordance with the. invention for the preparation of thermoplastics and duroplastics the continuous preparation and treatment of these substances in a single working operation becomes possible for the rst time.V The high speed of the mixing shaft tor the formation of the material ring in the mixing drum causes that in the material ring formed by the .raw materials of the plastic and in the additives such rictional heat is developed that the required mixing and jelling, as"well as granulation, if any, of the materials supplied to the mixing drum takes place in the mixing drum, and this without any application of pressure to the individual mixture components. The fact that this continuous working subsequently from the thermoplastics and duroplastics.

An essential advantage of the invention resides also in the fact that this continuous treatment operation takes place substantially more rapidly than it was possible to perform heretofore with the known machines for'the preparation and treatment of the plastics raw materials. The continuous preparation of plastics raw materials achieved for the rst time provides also for an essential decrease in labor.

ln accordance with the invention it is also Ypossible to add to the mixing and heating zone of the mixing drum for the preparation Aof the plastic raw materials in a unitary structure and in axial direction a drum section serving for the cooling operation. A

ln the case Where the machine in accordance with the invention is used as an ordinary mixing machine or as a machine for the lpreparation of Vplastic `raw materials, a further feature of the invention is of great signiiicance in accordance with which one or more closed disks rotating with the mixing shaft are provided, which are made of such size that they dip into the ring of material which is formed during the mixing or friction operation. This results in an interruption of the uncontrolled passage of light or possibly floating powder components in the open interior of the ring of material. AlsoV theV admixture components which have a tendency to oat are forced by these disks to enter the ringof material. Accordingly also these components are compelled to participate in the mixing operation. The high mixing intensity brings the mixture components so closely together that partially the surface forces cause mixture adherence inV such a manner that, depending on the product, some welding may take place. Y Y Y Further details of the invention will become apparent it' reference is had to the, accompanying drawings which illustrate an embodiment of a mixing machine for the continuous combined preparation of thermoplastics or shown in FIG. 3 including inserts which may be adjusted during operation to change the magnitude of the discharge opening, and FIG. is a partial sectional view illustrating the feature ofthe shaft being made in two sections.

The mixing machine comprises a drum 1 having at the supply or intake end an end wall 2 provided with a funnel 3. The wall 2 is formed as an annular disk having a circular aperture 4 in a manner that the raw materials of the plastic which are fed into the funnel 3 reach the interior of drum 1 by Way of the circular aperture 4. An annular disk 5 is also provided at the discharge end of the cooling drum. The material issuing from the mixing drum must pass through the 'aperture 6 of this annular disk S in order to leave the mixing drum through `the discharge duct 7.

A mixing shaft 8 is providedin the mixing drum 1 which is supported in the bearings 9 and 1t) and which is driven by way of the coupling device 11. The mixing shaft 8 is equipped with mixing tools 12 and 13.

The shaft 8 of the mixing machine is driven at such a speed of rotation that the centrifugal force produced thereby causes the raw materials of the plastic fed into the drum to be cast against the 'inner wall of the mixing drum 1 in a manner that a ring of material 14 is formed therein. The mixing shaft 8 is provided with additional disks mounted at an axial distance from one another, thediameter-of which is so chosen that the outer rim of these disks 15 projects into the ring of material 14. This means that all mixture components fed rinto the mixing drum must pass through the gap of the ring between the inner wall of the drum 1 and the outer rim of the disks 15 through the ring of material formed in the drum.

The mixing drum comprises the sections A and B. The drum section A serves for mixing and heating the raw materials of the plastic, in which`connection it is possible by the choice of the suitable number of revolutions of the mixing shaft in combination with the volume passed through the drum and the construction of the mixing arms to carry the heating so far that such a temperature develops which insures lthe desired jelling and softeningof the raw materials of the plastic without application of pressure.

In `the type of mixing machine illustrated the drum section A is joined directly to a drum section'B, which is defined in an axial extension of the drum and which serves for cooling the material that has been mixed and heated in section A. For -this purpose the mantle of the drum 1 is provided with an outer mantle 16 in the region of section B. A suitable cooling agent may be conducted through the annular space 17 by way of the hollow stubs 18 and 19. For the support of the cooling operation the mixing shaft 8 is provided with a smaller number of mixing arms 13 vin the region of the drum section B. As indicated schematically in the drawing, the shape of these mixing arms 13 in the cooling area B is different than in the drum region A lin a manner that they may, for example,V

be pointed so as to produce only as little frictional heat as possible. f

The coolingelfect 'in the drum section B may also be caused or supported byV subdividing the mixing shaft forthe drum section A andthe drum section liso that each' of the two mixing shafts may be provided with different driving means, in such a manner that the` mixing shaft for the cooling section B is drivenat a smaller `number ofV revolutions than the mixing shaft of the drumfV section A.V

able that the introduction of the softening agentintothe material being treated in the drum takes place only at a particular distance-from the supply aperture of the mixing drum. 'I'hisinsures a corresponding mixing ofthe powdered-components,'and amediumtemper'ature of the ma- Cil Y d terial being mixed is already attained which causes rapid penetration of the softener into the plastic materials.

It has furthermore been found to be of value in accordance with the invention that the required quantity of the softening component is not introduced suddenly -in one place to the material being mixed in the drum, but it is particularly valuable for the control of the Dry-Blend- Method Which is to be carried out that several entrance apertures for the softener are arranged in sequence axially of the drum. Under some conditions it is even desirable particularly for the sensitive PVC emulsions to extend the introduction of the softener through suitable distribution of the supply apertures even into the cooling zone.

The supply of the softener can be effected by means of injection nozzles 2i) which are provided on thefmantle of the drum 1, by means of which the softening agent is forced into the ring of material under suitable pressure The softening agent can be introduced in the mix -atV a relatively low pressure, if the injection nozzles-21 are provided at the free end of supply ducts 22 in the interior of the drum in suchV a manner that these supply vducts 22 extend through the ring of material 14.

In many cases it is particularly advantageous for the introduction of the softening agent to provide'the mixing` shaft 8 with an axial bore-23 and with suitable radial bores 24. The radial bores 24 must then be provided with" nozzles 25. At the right end of-the mixing shaft 8 a feed lcap 26 is arranged which is provided with a tubular supply,V At the left end of the stub 27 for the softening agent. mixing shaft S the axial bore 23 is closed by the plug 28. The softening agent supplied in cool condition by way of the stub 27 to the bore 23 of themixiug shaft 8 `firstmay be used for canying out the Dry-Blend-Method wherel the prepared thermoplastic or duroplastic leaves the mixing machine in pulverized or granulated form. Instead of the Dry-Blend-Method it is fundamentally also possible with the same machine by suitably greater heating insidethe heating zone A to discharge the treated material from the mixing drum in a more or less plastic condition, so that this plastic material may be directly supplied inthe form of lumps or cakes to a calendar for producing plastic sheets as the particular method may require. In this case the mixing drum is operated without a cooling area B. In accordance with the invention it is also possible in the production of the plastic product to carryout a continuous method of operation. For -this purpose it is recommended to suitably yadapt the mixing tools of the mixing shaft atthe discharge end of Vthe drum to ythe .par-` ticular conditions of the plastic material which prevail inJ that area.

The mixing shaft 8 is provided with a feed backthread 29 in the region'of the supply tunnel 3 and at the discharge end of the mixing drum.

The cross sectional illustration in accordance with FIG.

2 shows the mixing drum 1 having'an intake end wall 2 and a supply funnel 3. The intake aperture 4 in this case` is indicated in dashes as a circular aperture. Two mixing arms 1?; are shown on the mixing shaft 8 of FIG. 2 which? are displaced by Advantageously all mixing arms of this system are displaced by 180. However, other angular relationships can be employed, above all,` a helical arrangement which, depending upon the orientation, will promote or impede the passage' of the material.:

In FIG. 3 the mixing drum is illustrated again showingy the stop ring 5 as well asv the discharge duct 7. In'ac-i cordance with FIG". 3 the stop ring 5 is provided with a' circular discharge aperture 6. The stop ring 5 is mountedA on the drum in a manner to be readily exchangeable so.

that other stop rings having dilerent sizes of discharge apertures can be inserted. In this manner diierent volumes of material can be fed into the drum to obtain dierent mixing times for the material, while the volume remains the same, or it is also possible to adapt the volume to ditferent output quantities. A mixing arm 13 is mounted on shaft 8. A double mantle 16 is provided so that a cooling agent may be fed into the annular space 17. Depending on the use of the mixing machine the double mantle may also be provided in the region of drum section A so that a coolant or heating agent may be introduced there.

FIG. 4 shows a very similar arrangement as FlG. 3, but means are provided there to enable adjustment of the discharge aperture during'operation by way of adjustment of the cross sectional area of discharge. For this purpose stop ring 5 is provided with segments 3i) which can be pivotally moved about pins 3l so that the apertures 5 may be increased or decreased in cross sectional area. For the sake of clearness only three pivo-table segments are indicated. lt is, however, possible to provide such a number of segments as may be necessary that on moving the segments into the area of the discharge aperture, they approximate a circular area. A control arrangementV of the type used in connection with photographic cameras may be utilized. In order to obtain different shapes of discharge apertures it is also possible to use other known arrangements, for example, several radially adjustable segments.

In the embodiments in accordance with FIGS. l to 4 the material intake aperture and the material discharge aperture are of circular form, and they are concentric with the mixing shaft. The material intake aperture 4 is smaller than the material discharge aperture, and in particular the discharge aperture 4 is also smaller than the inner circular area that is left open by the ring of material. The mixing arms or mixing tools sweep with their ends only 40 -to 70% of the length of the mixing drum. The bore 23 of the mixing shaft 8 may also be used for introducing other substances to be added to the mix, depending on the use of the mixing machine.

The feature mentioned hereinabove of the shaft 8 being subdivided is shown in greater detail in FIG. 5. The ends of the two shafts 8 and 8a are journaled .in the bearing 8c which is supported by stationary struts or bars Sd which permits rotation of the shafts 8 and 8a at different angular velocities. Also in this embodiment of the invention a passage 23 may be provided for feeding an additive to nozzles such as 25 by Way of aperture 24.

The heating, the agglomeration or the jelling and the plastifying of the raw materials, if need be, until a complete cake or the like is formed, require only very short operating periods when the machine in accordance with the invention is used. The operations can be completed in 30 seconds and rarely require than 120 seconds.

Having now described my invention with reference to the embodiments illustrated in the drawings, I' do not wish to be limited thereto, but what I desire to protect by Letters Patent of lthe United States is set forth in the appended claims.

l claim:

1. Mixing machine for the continuous mixing of diff defining la discharge aperture and-a substantially ,hori-v material in said drum to form a ring of material circumferentially of the inner wall of said drum and at least one disk rotatable with said shaft and projecting therefrom ilnto said ring of material during mixing operations and defining a passage between the circumference thereof and said peripheral surface, said intake and said discharge apertures being disposed within the contines of the circular area encompassed by said ring of material, said end walls being substantially ring shaped and thus retaining the main part of said material near the circumference of said drum.

2. Mixing machine for the continuous mixing of different materials, primarily powdered substances, comprising a mixing drum extending substantially horizontally and having a rectilinear proiile internally presenting a generally smooth, continuous peripheral surface, material receiving means at one end Wall of said drum including means defining an intake aperture, material output means at the other end wall of said drum including means defining a discharge aperture and a substantially dhorizontal mixing shaft` extending through said drum and having a driving means, said shaft including stirring arms extending at different positions longitudinally of said shaft and radially therefrom into proximity of said pe-l ripheral surface operative to impart centrifugalV force to material in said drum to form a ring of material circumferentially of the inner wall of said drum and atleast one disk rotatable with said shaft and projectingftherefrom into said ring of material during mixing operations and defining a passage between the 'circumference thereof and said peripheral surface, said intake and said discharge apertures being disposed within theconiines of the circular area encompassed by said ring of material, said end walls bein(r substantially ring shaped and thus retaining the main part of said material near the circumference of said drum, and a plurality of injection apertures arranged inside said drum and spaced from said intake aperture for supplying an additive agent such as a softener to the material in said drum.

3. Mixing machine for the continuous mixing of different materials,v primarily powdered substances, comprising a mixing rum extending substantiallyghorizontally and having a rectilinear profile internally presentingv having a driving means, said shaft including stirring arms extending Vat diiferent positions longitudinally of said shaft and radially therefrom into proximity of said peripheral surface operative to impart centrifugal force to material in said drumk to form a ring of material circumferentially of the inner wall of said drum and at least` one disk rotatable with said shaft and projecting therefrom into said ring of material during mixing operations and deiining a passage between the circumference thereof and said peripheral surface, said intake and said discharge apertures being disposed within the confines of the circular area encompassed lby said ring of material, said end walls being substantially ring shaped and thus re'- taining the main part of said material near the circumference of said drum, and a plurality of injection apertures arranged inside said drum and spaced from said intake zontal mixing shaft extending through said drum and aperture for supplying an additive agent such as a softener to the material in said drum, said injection apertures being arranged axially of said drum.

4. Mixing machine for the continuous mixingV of different materials,`primanily powdered substances,A com-4 prising a mixing drum extending substantiallyV horizon?V tally and having a rectilinearproiile internally presenting a Agenerally smooth, continuous peripheral surface, material receiving means at one e-nd Wall of said drum including-means deiiningk anintake aperture, material output,

means at the other end wall of said drum lincluding means dening `a discharge aperture andv a substantially'horizontal mixing shaft extending through said drum and having a driving means, said shaft including stirring arms extending at different positions longitudinally of said shaft and radially therefrom into proximity of said peripheral surface operativeto impart centrifugal force to material in said drum to form a ring of material circumferentially of Ithe inner Wall of said drum and at least one disk rotatable with said shaft and projecting therefrom into said ring of material during mixing operations and defining a passage between the circumference thereof and said peripheral surface, said intake and said discharge apertures being disposed Within the contines of the circular area encompassed by said ring ofmaterial, said end walls being substantially ring shaped and thus retaining the main part of said mater-ial near the circumference of said drum, and a plurality of injection apertures arranged inside said drum and spaced from said intake aperture for supplying an additive agent such as a softener to thematerial in said drumpsaidrinjection apertures being in the form of nozzles mounted in the mantle of said drum and spaced axially from said disk, said nozzles beingv located inside said drum endwise of supply tubes extendingjthrough the ring of material intor the open inner space.

5. Mixing machine for the continuous mixing or" different materials, primarily powdered substances, compri-sing a mixing drum extending substantially horizontally and having a rectilinear prole internally presenting a generally smooth, continuous peripheral surface, material receiving means at one end Wall of said drum including means defining an intake aperture, material output means at the other end Wall of said drum including means defining a discharge aperture and a substantially horizontal mixing shaft extending through said drum and having a driving means, said shaft including stirring arms extending at different positions longitudinally of said shaft and radially therefrom into proximity of said peripheral surface operative to impart centrifugal force to material in said drum to form a ring of materiall circumferentially of `the inner wall of said drumrand at least one disk rotatable with said shaft and projecting therefrom into said ring of material dur-ing mixing-operations and defining a passage between the circumference thereof and said peripheral surface, said ,intake and .said discharge apertures being disposed `within the contines of the circular area encompassed by said ring of material, said end Walls 'being substantially ring shaped and thus retaining the main part of said material near the circumference of said drum, and a plurality of injection apertures arranged inside said drum and spaced from said intake aperture for supplying an additive agent such asa softener to the material in said drum, said injection apertures being provided in said shaft and spaced from said disk and said shaft having an axial bore in communication with said apertures to supply said additive agent thereto.

6. Mixing machine for the continuous mixing of different `materials, primarily powdered substances, comprising a mixing drum extending substantially horizontally and having a rectilinear profile internally presenting a generally smooth, continuous peripheral surfacematerial receiving means at one end Wall of said drum incmding means defining an intaker aperture, material output means at the other end wall of said drum including means defining la discharge aperture and a substantially horizontal mixing shaft extending through said'drum and having a driving means, said shaft including stirring arms extending at different, positions ylongitudinally of said shaft and radially therefrom into proximity of said peripheral surfacel operative to limpart centrifugal force to material insaiddrum to Aferm a ringk of material cirand said peripheral surface, saidintakeand saidv dis- V charge apertures being disposed Within the contines of the circular area encompassed by said ring of material, saidl end Walls being substantially ring shaped and thus retaining the main part Vofsaid-material near the circum-- ference of said drum, and a plurality of injection apertures arranged inside said drum` and-spaced from said intakeaperture for supplying an additive agent such as a softener to the material in said drum, said mixing drum having a mixing and heating zone at one end and havinga drum section constituting a cooling zone unitary with said=mixv ing and heating zone and in axial alignment therewith.

7. Mixingmachine for the continuous mixing of ditferent materials, primarily powdered substances, comprising a mixing drum extending substantially h0rizon. tally and having a rectilinear profile internally presenting a generally smooth, continuous peripheral surface, mate rial receiving means at one end Wall of said drum includ-` ing means defining an intake aperture, material output means at the other end wall of-said drum includingmeans deiining a discharge aperture and a substantially hori` zontal mixing shaft extending through said drum and` having a driving means, said shaft including stirring arms extending at different positions longitudinallyv of said shaft and radially therefrom into proximity of said-peripheral surface operative Ito impar-t centrifugal force tomaterial in said drum to forma ring of materialcircumferentially of ythe inner Wall of said drum and at least` one disk rotatable with said shaft and projectingthere-y from intosaid ring of material during mixing operations and defining a passage `between the Vcircumference thereof and said peripheral surface, said` intake and said discharge apertures being disposed within the contines of thecircular area-encompassed by said ring of material, said` end Walls Vbeing substantially ring shaped and thusretaining the main part Vof said material near the-circum-v ference of said drum, and a plurality of injection aperturesV arranged inside said drum and spaced fromsaid-intake aperture for supplying an .additive agent such as a softener to the material in said drum, said mixing drum having-a mixing andV heating zone -at oneend .and havinga drum,l section constituting a cooling zone unitary with said mixing and heating zone-and in axial aligrnent therewith, saidsection constituting said cooling zone having a ,double mantle defining a passage for the flow of coolant, and said arms in the area of said cooling zone being formed to effect minimum friction to favor cooling of the material.v

8. Mixing machinefor the continuous mixing of different materials, primarily powdered substances, com prising a mixing drum extending substantially horizontally and having a rectilinear profile internally presenting` a generally smooth, continuous peripheral surface, material receiving means at one end wall of said .drum including means defining an intake aperture, material output means at the. other end Wall of said drum Vincluding means defining a discharge aperture and a substantially hori- Y zontal mixing shaft extending through said drumV and having a driving means,.said shaft including stirring arms extending at different positions longitudinally of said shaft and radially the1-efrominto proximity of Vsaid peripheral surface operative to'impart centrifugal force .to material in said drum to form a ring of material circumferentially of Ithe inner Wall of said drum and at least one disk rotatable with said shaft and projecting there-y from into said ring of material during mixing operations and defining a passage between the circumference thereof and said peripheral surface, said intake and said discharge apertures being disposed Within the contines of thecircular areauencompassed by said ring of material, saidend Walls-being subs-tantially ring shaped andy thus 1'e taining the main part of said material near Vthe circum- 'cumferentially of the inner Wall of said duim and at leastr and defining a passage between` the'circumference thereof ference of saidrdrum,.jand a plurality ofjinjection aper tures arranged inside said drurnand spaced `from said in-l take aperture for supplying an additive agent such as a f softener Ito the material in saidkdrurn, said mixing drumV having a mixing and heating zone at one end and having a drum section constituting a cooling zone unitary with said mixing and heating zone and in axial alignment therewith, said mixing shaft being divided into two sections proximate the entrance to said cooling zone each provided with separate drive means and said shaft section in said cooling zone being rotatable at a slower speed than the section in said zone for mixing and heating.

9. Mixing machine for the continuous mixing of dif ferent materials, primarily powdered substances, comprising a mixing drum extending substantially horizontally and having a rectilinearprole internally presenting a generally smooth, continuous peripheral surface, material receiving means at one end wall of said drum including means defining an intake aperture, material output means at the other end wall of said drum including means defining a discharge aperture and a substantially horizontal mixing shaft extending through said drum and having a driving means, said shaft including stirring arms extending at different positions longitudinally of said shaft and radially therefrom into proximity of said peripheral surface operative to impart centrifugal force to material in said drum to form a ring of material circumferentially of Ithe inner wall of said drum and at least one disk rotatable with said shaft and projecting there-` from into said ring of material during mixing operations and defining a passage between the circumference thereof and said peripheral surface, said intake and said discharge apertures being disposed within the connes of the circular area encompassed by said ring of material, said end walls being substantially ring shaped and thus retaining the main part of said material near the circumference of said drum, and a plurality of injection apertures arranged inside said drum and spaced from said'intake aperture for supplying an additive agent such as a softener to the material in said drum, said intake aperture and said discharge aperture being substantially circular and concentric with said mixing shaft and said intake aperture being smaller in cross-sectional area than said discharge aperture. v

Mixing machine for the continuous mixing of different materials, primarily powdered substances, comprising a mixing drum extending substantially horizontally and having a rectilinear profile internally presenting a generally smooth, continuous peripheral surface, material receiving means at one end wall of said drum includ- 10 ing means defining an intake aperture, material output means at the other end wall of said drum including means defining a discharge aperture and a substantially horizontal mixing shaft extending through said drum and having a driving means, said shaft including stirring arms extending at dierent positions longitudinally of said shaft and radially therefrom into proximity of said peripheral surface operative to impart centrifugal force to material in said drum to form a ring of material circumferentially of ythe inner wall of said drum and at least one disk rotatable with said shaft and projecting therefrom into said ring of material during mixing operations and defining a passage between the circumference thereof and said peripheral surface, said intakev and said discharge apertures being disposed Within the coniines of the circular area encompassed by said ring of material, said end walls being substantially ring shaped and thus retaining the main part of said material near the circumference of said drum, said means defining said discharge aperture being removable for replacement by elements having different diameters, and being provided with adjustable segments or the like adjustable during operation for varying the cross-sectional area of the discharge aperture.

References Cited by the Examiner UNITED STATES PATENTS 52,2'68 1/66 Chapman 259-25 122,870 1/72 Vanatter -2'59-105 228,319 6/ 80 Cornwall et al. 259-136 1,816,453 7/31 Willard 259-9 1,983,782 12/34 Shropshire 259-9 2,029,690 2/3'6 Wilson 259-9 X 2,080,327 5/37 McKinnis 259-6 2,649,272 8/53 Barbato V 251-212 2,721,359 10/55 Morgan 259-97 X 2,746,730 t 5/56 Swenson et al. 259-9 2,791,404 5/57 Kelley et al. 259-9 Y 2,836,401 5/58 Phelan 259-9 X 2,894,733 7/59 Wosmek 259-97 X 2,907,555 10/59 Engels 259-9 2,961,213 11/60 Vl'hilippovic 251-4 WALTER A; SCHEEL, Primary Examiner.

LEO QUACKENBUSH, Examiner. 

1. MIXING MACHINE FOR THE CONTINUOUS MIXING OF DIFFERENT MATERIALS, PRIMARILY POWDERED SUBSTANCES, COMPRISING A MIXING DRUM EXTENDING SUBSTANTIALLY HORIZONTALLY AND HAVING A RECTILINEAR PROFILE INTERNALLY PRESENTING A GENERALLY SMOOTH, CONTINUOUS PERIPHERAL SURFACE, MATERIAL RECEIVING MEANS AT ONE END WALL OF SAID DRUM INCLUDING MEANS DEFINING AN INTAKE APERTURE, MATERIAL OUTPUT MEANS AT THE OTHER END WALL OF SAID DRUM INCLUDING MEANS DEFINING A DISCHARGE APERTURE AND A SUBSTANTIALLY HORIZONTAL MIXING SHAFT EXTENDING THROUGH SAID DRUM AND HAVING A DRIVING MEANS, SAID SHAFT INCLUDING STIRRING ARMS EXTENDING AT DIFFERENT POSITIONS LONGITUDINALLY OF SAID SHAFT AND RADIALLY THEREFROM INTO PROXIMITY OF SAID PERIPHERAL SURFACE OPERATIVE TO IMPART CENTRIFUGAL FORCE TO MATERIAL IN SAID DRUM TO FORM A RING OF MATERIAL CIRCUMFERENTIALLY OF THE INNER WALL OF SAID DRUM AND AT LEAST ONE DISK ROTATABLE WITH SAID SHAFT AND PROJECTING THEREFROM INTO SAID RING OF MATERIAL DURING MIXING OPERATIONS AND DEFINING A PASSAGE BETWEEN THE CIRCUMFERENCE THEREOF AND SAID PERIPHERAL SURFACE, SAID INTAKE AND SAID DISCHARGE APERTURES BEING DISPOSED WITHIN THE CONFINES OF THE CIRCULAR AREA ENCOMPASSED BY SAID RING OF MATERIAL, SAID END WALLS BEING SUBSTANTIALLY RING SHAPED AND THUS RETAINING THE MAIN PART OF SAID MATERIAL NEAR THE CIRCUMFERENCE OF SAID DRUM. 